1. Field
Example embodiments relate to a lens positioning unit of an optical system usable with an exposure apparatus, which performs lens position adjustment with one degree of freedom of micron-level precision within a minimum space.
2. Description of the Related Art
In order to assemble a barrel type optical system usable with an exposure apparatus, a large-diameter lens may be mounted in a unit cell barrel and precise stacking of cells may be performed.
The optical system assembled in the above-described manner may require adjustment of an infinitesimal axial distance between lenses for correction of magnification and aberration. In this case, reducing and/or preventing parasitic motion in directions other than an axial direction may be desired.
A screw type device may be used to adjust the distance between lenses. The screw type device may have an inner surface to which a lens is secured and the screw type device may serve to adjust the height of the lens via rotation thereof. However, this method causes rotation of an optical axis of the lens and has difficulty realizing pure vertical motion due to backlash and irregularity of screws.